package com.nulldev.util.data.Arrays.maps.trie;

import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;

abstract class MainNode<K, V> extends BasicNode {

	@SuppressWarnings("rawtypes")
	public static final AtomicReferenceFieldUpdater<MainNode, MainNode> updater = AtomicReferenceFieldUpdater.newUpdater(MainNode.class, MainNode.class,
			"prev");

	public volatile MainNode<K, V> prev = null;

	public abstract int cachedSize(Object ct);

	public boolean CAS_PREV(MainNode<K, V> oldval, MainNode<K, V> nval) {
		return updater.compareAndSet(this, oldval, nval);
	}

	public void WRITE_PREV(MainNode<K, V> nval) {
		updater.set(this, nval);
	}

	// do we need this? unclear in the javadocs...
	// apparently not - volatile reads are supposed to be safe
	// regardless of whether there are concurrent ARFU updates
	@SuppressWarnings("unchecked")
	public MainNode<K, V> READ_PREV() {
		return updater.get(this);
	}

}